I have a Sony VPCS13C5E and I want to boot from efi but Sony has disabled it. Can you try to enable efi boot and some hidden setup menu lke advanced or debug?Here is bios download: http://ftp.ftp.vaio-link.com/pub/VAIO/UPDATES/EP0000229946.EXEIt's 2100Q3 version.It seems it's for all VPCS13 model so I won't be alone to use it.Ask me if you need some screenshot.